I found warming it in my hand after drawing the oil into the syringe to be all that was required, just hold it tightly for a few minutes and it will warm up. Im currently pinning 3ml twice a week using orange 25g 1.5" needle, only time I really had issues was with a dicky needle (not sure about other countries but in NZ we get all needles/syringes etc for free) but some of them are cheaply assembled though by the looks, needle sometimes protrudes out of the plastic on an angle. Or if I don't wait for the alcohol from the wipe to dry before pinning that'll hurt ya too. Used both Test E and C with varying carrier oils